FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFIC A TION
(See section 10, rule 13)
1. Title of the invention
A DEVICE FOR MEASURING THE FLOW OF LIQUID
2. Applicant(s)
Name Nationality Address
TATA CONSULTANCY SERVICES LTD. INDIA TCS HOUSE, RAVELINE STREET, 21 D S MARG,
MUMBAI FORT, MUMBAI-400001
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it is
to be performed.

The invention relates to a device for measuring the flow of liquid. The invention also relates to a device for indication of measurement and stoppage of flow of liquid through the device after a predetermined quantity of liquid has passed through the device.
BACKGROUND
Water treatment devices are well known in the art. Such devices are employed directly in a water system, either in-line or at a terminal end, or in self-contained batch systems.
Conventional water treatment devices employ mechanical filtration or chemical treatment. Mechanical filters treat water by preventing passage of particulate matter and /or microorganisms. As a mechanical filter approaches the end of its useful life, restricted flow due to accumulation provides a ready indication that element replacement is necessary.
Chemical treatment (e.g., activated carbon-based and ion exchange media) employs processes such as adsorption and ion exchange for removing / inactivating undesirable chemical and microbiological species. A major drawback associated with chemical treatment is that the chemical media eventually becomes inactive, providing no indication that the useful life of the device has been exceeded.
As a result, various methods have been employed to indicate the flow of liquid or end of life to the user where it is not inherently provided by the behaviour of the filter media.
A more accurate means of indicating the flow of liquid or end of useful life of a water treatment unit is through devices which use a process commonly referred to as "flow totalization". These devices totalize the liquid volume which has passed through the treatment media and indicate the end of useful life to the user.
Both electrical and mechanical "flow totalization" devices are known in the art. While both electrical and mechanical devices address the end of life problem, there are drawbacks. Electronic totalizers require batteries as power sources which are expensive hence making the cost of the totalizing device to become comparable to the purification cartridge itself. Mechanical totalizers described in the art are complicated in nature and hence expensive and fragile.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1 illustrates a liquid purification cartridge in accordance with an embodiment of the invention.

Figure 2 is a schematic cross-sectional illustration of the liquid purification cartridge in accordance with an embodiment of the invention.
Figure 3 illustrates an exploded view of a device for measuring the flow of liquid in the cartridge in accordance with an embodiment.
Figure 4 shows the exploded view of a plate, a lever and a gear in accordance with an embodiment.
SUMMARY
A device for measurement of flow of liquid is disclosed. The device includes a plate defining a recess and a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm. The device further includes a lever mounted on the plate comprising of an upper jaw and a lower jaw. The lower jaw of the lever is operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever. The device further includes a gear defining an upper surface and a lower surface. The upper and the lower surface each comprise of a plurality of teeth such that a tip of the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth on the lower surface. The gear is mounted on the plate such that the upper jaw of the lever is configured to engage with any of the plurality of teeth on the upper surface of the gear and the lower jaw of the lever is configured to engage with any of the plurality of teeth on the lower surface of the gear. The gear is further configured to be under torsional tension to make it rotate unidirectionally such that the movement of the lever by the diaphragm causes the lever to release the torsional tension on the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
By way of example, the invention is described in detail as a flow measurement device used in a liquid purification cartridge. The liquid purification cartridge is configured to receive liquid from a source. The liquid pressure at any point depends upon the level of liquid in the source. The pressure in the cartridge increases with increase in the level in the source and it decreases with decrease of the level in the source. The diaphragm moves downwards with an increase in the level of liquid in the source. The diaphragm will also deflect down with increase of liquid pressure above the diaphragm. As liquid flows out of the liquid purification cartridge, the pressure above the diaphragm decreases and causes the diaphragm

"•""to deflect upwards back to its normal position. Such deflections of the diaphragm may cause the gear to rotate. Every rotation of the gear is indicated by an indicator. After a pre-specified number of rotations of the gear, a passage opening is blocked by the indicator and liquid flow through the liquid purification cartridge is stopped.
DETAILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof. Throughout the patent specification, a convention employed is that in the appended drawings, like numerals denote like components.
Reference throughout this specification to "one embodiment" "an embodiment" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment", "in an embodiment" and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
The present invention relates to a device for measurement of flow of liquid. In accordance with an aspect, the device includes a plate defining a recess and a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm.
The device further includes a lever with an upper jaw and a lower jaw mounted on the plate. The lower jaw of the lever is operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever.
The device further includes a gear defining an upper surface and a lower surface. The upper and the lower surface each comprise of a plurality of teeth such that a tip of the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth

'on the lower surface, the gear mounted on the plate such that the upper jaw of the lever is configured to engage with the plurality of teeth on the upper surface of the gear and the lower jaw of the lever is configured to engage with the plurality of teeth on the lower surface of the gear.
In accordance with an aspect, the gear is under torsional tension to make it rotate unidirectionany such that the movement of the lever by the diaphragm causes the lever to release the torsional tension on the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
According to an embodiment, the device is further configured to indicate and stop the flow of liquid.
By way of example, the invention is described in detail as a flow measurement device (29) used in a liquid purification cartridge (1). A liquid purification cartridge (1) is illustrated in Figure 1.
Figure 2 is a cross sectional schematic illustration of the liquid purification cartridge (1) in accordance with an embodiment. Figure 2 shows the path of flow of the liquid (indicated by arrows) inside the liquid purification cartridge (1). The liquid purification cartridge (1) comprises of an outer casing (2), an inner casing (3), an inlet lid (9), a breather (7), a channel (10) and a purifier/ filters (not shown).
Referring to Figure 3 illustrating an exploded view of a device (29) for measuring the flow of liquid in the cartridge (1) along with Figure 2, the device (29) comprises of a plate (6), a diaphragm (8), a lever (15) and a gear (12). The device (29) further comprises of an indicator (13), and a string (11). A passage opening (4) is provided in the channel (10) of the device (29).
Referring back to Figure 2, the liquid purification cartridge (1) is configured to receive liquid from a source (not shown). The liquid enters into the liquid purification cartridge (1) through the inlet lid (9). The liquid travels down through the channel (10) between the outer casing (2) and the inner casing (3) and then travels to the bottom of the liquid purification cartridge (1) through the passage opening (4) defined in the channel (10). From the bottom of the liquid purification cartridge (1), liquid rises up through the inner casing (3) and enters into a cavity (5) in the base-plate (6). The liquid comes down through the breather (7) and exits the liquid purification cartridge (1).

Still referring to Figures 2 and 3, the plate (6) is fitted on the inner casing (3). The plate (6) defines a recess (5) and an opening (16) within the recess (5). The opening (16) is positioned above the breather tube (7) for the liquid to exit the liquid purification cartridge (1). Liquid enters into the recess (5) through a nozzle (17). Liquid exits the liquid purification cartridge (1) through the breather (7). The breather (7) may be open to the atmosphere at its bottom end.
A diaphragm (8) is positioned within the recess (5) and configured to move upwards and downwards corresponding to a liquid pressure generated above the diaphragm (8).
According to an embodiment, liquid pressure at any point depends upon the level of liquid in the source. The pressure in the cartridge (1) increases with increase in the level in the source and it decreases with decrease of the level in the source. The diaphragm (8) moves downwards with an increase in the level of liquid in the source. The diaphragm (8) will also deflect down with increase of liquid pressure above the diaphragm (8). As liquid flows through the opening (16), the level in the source and pressure above the diaphragm (8) decreases and hence, the diaphragm (8) will deflect upwards back to its normal position.
According to an embodiment, each upward or downward deflection of the diaphragm (8) equals to one cycle of filling and emptying of the source. The deflections of the diaphragm (8) are oscillatory in nature.
According an alternative embodiment, the recess (5) is maintained at atmospheric pressure via a breather (7), one end of which is attached to the inside of the recess (5) while the other end is open to the atmosphere. The diaphragm (8) senses the pressure difference between the top of the base plate (6) and the atmosphere and deflects with changes in this pressure difference.
Referring to Figure 3 and 4, the lever (15) comprises of an upper jaw (23), a lower jaw (22) and a socket (21). The lever is mounted on the plate (6) at a support (18). The support (18) defining a hole (20). A pin (19) is inserted into the hole (20) of the support (18) and the socket (21) of the lever (15) after placing the lever inside the support (18). The bottom surface of the lower jaw (22) of the lever (15) is operationally connected to the diaphragm (8) such that the movement of diaphragm causes corresponding movement of the lever (15). When the water level in the source increases, the pressure on diaphragm (8) also increases. As a result of this increase in pressure, diaphragm (8) deflects downward. Since bottom surface of the lower jaw (22) of the lever (15) is attached to the diaphragm (8), the lever (15) moves down with the deflection of the diaphragm (8).

Referring to Figure (4), the gear (12) defines an upper surface (26) and a lower surface (27). The upper and the lower surface (26, 27) of the gear (12) each comprise of a plurality of teeth such that a tip of the gear tooth on the upper surface (26) is angularly displaced from a tip of the corresponding gear tooth on the lower surface (27). The gear (12) is fixed through an axle (14) on the base-plate (6) such that the upper jaw (23) of the lever (15) is configured to engage with any one of the plurality of teeth on the upper surface (26) of the gear (12) and the lower jaw (22) of the lever (15) is configured to engage with any one of the plurality of teeth on the lower surface (27) of the gear (12).
The gear (12) is further configured to be under torsional tension to make it rotate unidirectionally. The string (11) is wound over the axle (14) on the plate (6). The other end of the string (11) is attached to the indicator (13) which hangs in the channel (10). The indicator (13) keeps the string (11) under tension. The string (11) causes the gear (12) to be under torsional tension and makes the gear (12) rotate unidirectionally.
The gear may also be kept under torsional tension by an elastic string, a spring or other mechanisms including the use of magnets.
The device (29) is configured such that the teeth of the gear (12) are always engaged with one of the jaws (22, 23) of the lever (15), so that the gear (12) cannot rotate freely.
According to a specific embodiment of the invention, the lower jaw (22) of the lever (15) is engaged with the lower teeth (25) of the gear (12). When the level of liquid rises in the source, the pressure on the diaphragm (8) increases. As a result of this increase in pressure, the diaphragm (8) deflects downwards. The lever (15) being attached to the diaphragm (8) also moves down. In the process of moving down, the lower jaw (22) of the lever (15) disengages from its current tooth on the lower surface (27) of the gear (12) and the upper jaw (23) of the lever (15) engages the next tooth on the upper surface (26) of the gear (12). In the process of the engagement and disengagement of the jaws (22) and (23) of the lever (15) in the gear (12), the gear (12) rotates equal to the minimum angular distance between the tooth on the upper surface (26) and the lower surface (27) of the gear (12). With this rotation of the gear (12), the string (11) is unwound and the indicator (13) moves downward in the channel (10).
With the passage of liquid through the cartridge (1), the liquid level in the source decreases. With the decrease in liquid level in the source, the pressure on the diaphragm (8) also decreases. With this decrease in pressure, the diaphragm (8) rebounds back to its original position. With this motion of the diaphragm (8), the lever (15) also moves up. In this process,

'"' the upper jaw (23) of the lever (15) disengages from the tooth on the upper surface (26) of the gear (12) and the lower jaw (22) of the lever (15) engages the next tooth on the lower surface (27) of the gear (12). This process of engagement and disengagement of jaws (22) and (23) of the gear (12) makes the gear (12) rotate equal to the minimum angular distance between the upper teeth (24) and the lower teeth (25) of the gear (12). With this rotation of the gear (12), the string (11) gets further unwound and indicator (13) moves further down. This completes one cycle of filling and emptying of the source.
According to an embodiment, the above cycle is repeated with each filling and emptying of the source. With every such cycle, the string (11) unwinds and indicator (13) moves further down the channel (10). At the end of a predefined number of cycles, the indicator (13) moves towards the bottom of channel (10) and blocks the passage opening (4) positioned in channel (10) to stops the flow of liquid through the cartridge (1).
According to an embodiment, the passage opening (4) and the indicator (13) together form a valve (28). The valve (28) is open when indicator is hanging in the channel (10). The passage opening (4) gets closed when indicator (13) sits on it. This closing stops further flow of water through the passage opening (4).
According to an embodiment, the number of windings of string (11) on the gear (12) decides the number of rotations of the gear (12) before stoppage of flow of liquid through the liquid purification cartridge (1).
According to an embodiment, the number of teeth on gear (12) multiplied by the number of turns of the string (11) on the gear (12) equals the number of cycles purified before the stoppage of flow of water through the liquid purification cartridge (1).
According to an embodiment, the diaphragm (8) is made of flexible material.
According to an embodiment, the source may be a liquid reservoir positioned outside the cartridge (1) configured to provide a continuous supply of liquid to the cartridge (1).
SPECIFIC EMBODIMENTS ARE DESCRIBED BELOW
A device for measurement of flow of liquid comprising a plate defining a recess, a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm, a lever mounted on the plate comprising of an upper jaw and a lower jaw, the lower jaw of the lever operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever and a gear comprising of an upper surface and a lower surface, the

' upper and the lower surface each comprising a plurality of teeth such that a tip of the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth on the lower surface, the gear mounted on the plate such that the upper jaw of the lever is configured to engage with the plurality of teeth on the upper surface of the gear and the lower jaw of the lever is configured to engage with the plurality of teeth on the lower surface of the gear; and the gear further configured to be under torsional tension to make it rotate unidirectionally such that the movement of the lever by the diaphragm causes the lever to temporarily disengage the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
Such device(s), further comprising an indicator configured to display flow measurement, wherein the indicator is connected to the gear such that the rotation of the gear results in movement of the indicator.
Such device(s), wherein the indicator is connected to the gear by a string such that weight of the indicator keeps the gear under torsional tension.
Such device(s), wherein the indicator is positioned in a channel through which the liquid flows and is configured to provide a visual indication of flow measurement.
Such device(s), wherein the channel comprises of a passage opening through which liquid flows out of the channel and further the indicator configured to block the passage opening subsequent to a pre-determined number of rotations of the gear.
Such device(s), further comprising a spring operatively connected to the gear to keep the gear under torsional tension.
Such device(s), wherein the diaphragm is made of flexible material.
Such device(s), wherein the pressure below the diaphragm is substantially atmospheric pressure.
A purification cartridge including a device for measurement of flow of liquid comprising a plate defining a recess, the plate positioned below an inlet of the purification cartridge, a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm, a lever mounted on the plate comprising of an upper jaw and a lower jaw, the lower jaw of the lever operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever and a gear comprising of an upper surface and a lower surface; the upper and the lower surface each comprising a plurality of teeth such that a tip of

the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth on the lower surface, the gear mounted on the plate such that the upper jaw of the lever is configured to engage with the plurality of teeth on the upper surface of the gear and the lower jaw of the lever is configured to engage with the plurality of teeth on the lower surface of the gear and the gear further configured to be under torsional tension to make it rotate unidirectionally such that the movement of the lever by the diaphragm causes the lever to temporarily disengage the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
Such purification cartridge(s), comprising an outer container and an inner container; the outer and inner container defining a channel for flow of liquid in between, the channel comprising a passage opening for the exit of liquid from the channel, the channel further comprising an indicator configured to display flow measurement, wherein the indicator is connected to the gear such that the rotation of the gear results in movement of the indicator.
Such purification cartridge(s), wherein the indicator is configured to block the passage opening subsequent to a pre-determined number of rotations of the gear.
INDUSTRIAL APPLICABILITY
The device (29) for measurement of liquid flow of the present invention substantially reduces or eliminates the disadvantages and shortcomings associated with the conventional devices and/or methods.
The device (29) is simple, accurate and reliable. The device (29) comprises of fewer moving parts. The device (29) can be used in various applications where liquid flow is required to be measured in cycles or batches.
The device (29), as disclosed, may be reused a number of times. The device (29) can stop flow of liquid after a predefined number of cycles or batches passed and works without interfering with the flow of liquid through the device (29).
The device (29), as disclosed, may be used as a life indicator and stopping device for a gravity driven water purifier. In such purifiers, water flows from source to destination reservoirs under the influence of gravity and gets purified while passing through a purification cartridge. The device (29), as disclosed, can fit in the cartridge, measure the number of cycles of water purified, indicate the measurement to the user and stop the flow of water through the cartridge after a predefined number of purified cycles.

While example embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims.

WE CLAIM:
1. A device for measurement of flow of liquid comprising;
a plate defining a recess;
a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm;
a lever mounted on the plate comprising of an upper jaw and a lower jaw; the lower jaw of the lever operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever;
a gear comprising of an upper surface and a lower surface; the upper and the lower surface each comprising a plurality of teeth such that a tip of the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth on the lower surface, the gear mounted on the plate such that the upper jaw of the lever is configured to engage with the plurality of teeth on the upper surface of the gear and the lower jaw of the lever is configured to engage with the plurality of teeth on the lower surface of the gear; and the gear further configured to be under torsional tension to make it rotate unidirectionally;
such that the movement of the lever by the diaphragm causes the lever to temporarily disengage the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
2. The device as claimed in claim 1 further comprising an indicator configured to display flow measurement, wherein the indicator is connected to the gear such that the rotation of the gear results in movement of the indicator.
3. The device as claimed in claim 2 wherein the indicator is connected to the gear by a string such that weight of the indicator keeps the gear under torsional tension.

4. The device as claimed in claims 2 or 3 wherein the indicator is positioned in a
channel through which the liquid flows and is configured to provide a visual
indication of flow measurement.
5. The device as claimed in claim 4 wherein the channel comprises of a passage
opening through which liquid flows out of the channel and further the indicator
configured to block the passage opening subsequent to a pre-determined number of
rotations of the gear.
6. The device as claimed in claim 1 comprising a spring operatively connected to the gear to keep the gear under torsional tension.
7. The device as claimed in claim 1 wherein the diaphragm is made of flexible material.
8. The device as claimed in claim 1 wherein the pressure below the diaphragm is substantially atmospheric pressure.
9. A purification cartridge including a device for measurement of flow of liquid comprising:
a plate defining a recess, the plate positioned below an inlet of the purification cartridge;
a diaphragm positioned within the recess and configured to move upwards and downwards corresponding to liquid pressure generated above the diaphragm;
a lever mounted on the plate comprising of an upper jaw and a lower jaw; the lower jaw of the lever operationally connected to the diaphragm such that movement of the diaphragm causes corresponding movement of the lever;
a gear comprising of an upper surface and a lower surface; the upper and the lower surface each comprising a plurality of teeth such that a tip of the gear tooth on the upper surface is angularly displaced from a tip of the corresponding gear tooth on the lower surface, the gear mounted on the plate such that the upper jaw of the lever is configured to engage with the plurality of teeth on the upper surface of the

gear and the lower jaw of the lever is configured to engage with the plurality of teetr. on the lower surface of the gear; and the gear further configured to be under torsional tension to make it rotate unidirectionally;
such that the movement of the lever by the diaphragm causes the lever to temporarily disengage the gear by alternatively engaging a tooth on the upper surface and the lower surface of the gear thereby making the gear rotate equal to the angular distance between a tooth on the upper surface and the lower surface of the gear.
10. A purification cartridge as claimed in claim 9 comprising an outer container and an inner container; the outer and inner container defining a channel for flow of liquid in between, the channel comprising a passage opening for the exit of liquid from the channel, the channel further comprising an indicator configured to display flow measurement, wherein the indicator is connected to the gear such that the rotation of the gear results in movement of the indicator.
11. A purification cartridge as claimed in claim 10 wherein the indicator is configured to block the passage opening subsequent to a pre-determined number of rotations of the gear.
12. A device for measurement of flow of liquid substantially as herein described with reference to and as illustrated in the accompanying drawings.